Both training methods made athletes jump higher and turn faster, but didn’t make them run straight-line sprints any faster.

Scientific Claim

Six weeks of either unilateral or bilateral eccentric-overload training is associated with improved counter-movement jump height and 90° change-of-direction performance in young male team sport athletes, but no meaningful change in 10-meter sprint time, indicating these training methods enhance explosive power and directional control without improving straight-line speed.

Original Statement

“Both groups improved CMJ, POWER, POWERd, POWERnd, COD90 and DEC-COD90, without changes in T-10m.”

From study:The effects of unilateral and bilateral eccentric overload training on hypertrophy, muscle power and COD performance, and its determinants, in team sport players

Evidence Quality Assessment

Claim Status

overstated

Study Design Support

Design supports claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The authors use 'induce substantial improvements'—causal language. The design cannot support causation; only associations between training and outcomes can be claimed.

Evidence from Studies

Supporting (1)

The effects of unilateral and bilateral eccentric overload training on hypertrophy, muscle power and COD performance, and its determinants, in team sport players

Randomized Controlled Trial

Human

2018

This study found that doing special strength exercises for six weeks made athletes jump higher and turn faster, but didn’t make them run the 10-meter sprint any quicker — which is exactly what the claim says.

Contradicting (0)

No contradicting evidence found

Source Study

The effects of unilateral and bilateral eccentric overload training on hypertrophy, muscle power and COD performance, and its determinants, in team sport players

Score: 46

DOI: 10.1371/journal.pone.0193841

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